This invention relates generally to a method for re-routing of mobile vehicles. In particular, this invention relates to a method for determining one or more alternative routes around a traffic incident site, and an assignment algorithm for distributing the traffic.
With increasing levels of traffic on rural and metropolitan roads, the propensity for traffic accidents, vehicle failures, emergencies and construction on the roadway increases the need for operational vehicles to be effectively re-routed past the affected site or re-routed avoiding the area altogether. Re-routing of traffic around an incident site is of particular importance on expressways, freeways, highways and major arterial roads where the movement of a large number of mobile vehicles may be detrimentally affected. A traffic incident site may include an accident, a slowdown, a blockage of a road segment or a construction area.
Historically, a variety of methods have been used to determine alternative pathways past a traffic incident site. Simple methods include driving on road shoulders and median strips, or moving around the site by following visual directions given by police officers, traffic control personnel or detour signs. Other methods include following behind other vehicles to off-ramps and through local city streets, or unwittingly traversing an alternative route using road signs, landmarks and other means in an attempt to maintain proper direction. If maps or an autonomous geographical information system are available onboard, then they may be consulted for information on alternative routes. Traffic information may also be available from local radio stations, giving locations of traffic incident sites, updated status or suggestions for alternative routes. An individual vehicle operator may also simply wait or move forward on the originally chosen roadway until the incident is passed by, not knowing if maneuvers onto local streets would offer any time benefits.
These approaches may provide a locally acceptable route for bypassing a traffic incident site, however, they neither offer a method for optimization where many vehicles may be affected, nor provide a methodology for an individual vehicle or a multiplicity of vehicles to rapidly get past a traffic incident site. Nor do these approaches provide feedback on the success of alternative routes, or provide for traffic re-distribution over multiple routes. Nor do these approaches provide the mobile vehicle operator with the latest information on current data such as traffic conditions, road construction and other conditions or preferences that may impact the route selection process. Furthermore, these approaches may not provide hands-free operation while selecting or driving along an alternative route, or may not provide accurate, verbal interactions with a real or virtual advisor for exploring possibilities and determining an appropriate exit point, local directions, and a re-entry point to the intended vehicle route.
Inclusion of telematic devices on an increasing number of newer vehicles presents the opportunity for vehicle operators to request information regarding an incident and alternative routes around the incident site. Simply re-routing of all subscribers on a presumed optimal path around an incident site re-routes all subscribers to a new, singular path. All of the vehicles traversing this new path run the risk of creating a new slowdown, or creating a new incident. A method is needed to efficiently and reliably distribute the traffic load around an incident site.
It would be desirable, therefore, to provide a method for generating alternative routes for a mobile vehicle that overcomes the limitations of re-routing methods mentioned above.
One aspect of the invention provides a method for routing traffic around a traffic incident. A traffic incident location may be provided, along with an intended vehicle route. A polygon may be determined around the traffic incident site and may contain at least one exit point from the intended vehicle route and at least one route re-entry point. Within this polygon, a number of intersections including the route exit point and the route re-entry point may be determined. Between each intersection, a link value or weight may be assigned. The link weights may be based on at least one condition factor. One or more alternative routes between the route exit point and the route re-entry point may be determined, based on the assigned link weights.
The link weights between the identified intersections may be equal to the distance between the intersections, for example, in miles. The link weights may also be based on other condition factors, such as travel time between intersections; orientation of the link with respect to the intended vehicle route; number of traffic lights, duration of each traffic light and their synchronization; local speed limit; number of stop signs, left turns, lanes, cross streets and driveways; road conditions, traffic backup and other points of interest between the intersections; dynamic traffic information, statistically relevant and real time traffic information; time of day; weather; gas requirements; vehicle wear and tear; and personal preferences.
The algorithm for determining the alternative route may be based on local optimization between intersections. One or more alternative routes, however, may be based on selecting a link weight corresponding to a greatest distance between intersections. The alternative routes may be labeled, and assigned to the mobile vehicle based on a traffic re-distribution algorithm. The traffic re-distribution algorithm may simply be a round-robin method, assigning each vehicle, in turn, to one of the labeled routes.
Another aspect of the current invention provides a computer usable medium including a program for determining mobile vehicle routing around a traffic incident site.
The program may include computer program code that receives the location of a traffic incident. The program may also include computer program code that receives an intended mobile vehicle route. The program may include computer program code that determines a polygon based on the traffic incident location and intended vehicle route. The program may include computer program code that determines at least one route exit point and at least one route re-entry point. The program may include computer program code that determines a plurality of intersections within the polygon, and may assign weights to links between the intersections based on at least one condition factor. The program may include computer program code that determines at least one alternative route between the exit point and re-entry point based on the assigned link weights.
The program may also include computer program code that labels each alternative route, and assigns one of the labeled routes to the mobile vehicle using a traffic re-distribution algorithm.
Another aspect of the present invention provides a system for mobile vehicle routing around a traffic incident. The system may include a means for receiving a traffic incident location and a means for receiving an intended vehicle route. The system may also include a means for determining a polygon containing the traffic incident location, a means for determining at least one route exit point and at least one route re-entry point, a means for determining a plurality of intersections within the polygon, a means for assigning weights to links between the intersections, and a means for determining at least one alternative route between the route exit and the route re-entry points.
The system for mobile vehicle routing around a traffic incident may also contain a means for assigning an alternative route to a mobile vehicle.